Head configuration for a threaded fastening member



y 970 v. R. MITCHELL 3,511,118

HEAD CONFIGURATION FOR A THREADED FASTENING MEMBER Filed May 6, 1968 INVENTOR.

Vernon R. Mitchell BY Fig. 6 h fi 3,

A TTOPNE Y United States Patent O 3,511,118 HEAD CONFIGURATION FOR A THREADED FASTENING MEMBER Vernon R. Mitchell, 437 Lake Michigan Drive NW., Grand Rapids, Mich. 49504 Filed May 6, 1968, Ser. No. 726,841 Int. Cl. B25b 13/02 US. Cl. 81119 1 Claim ABSTRACT OF THE DISCLOSURE A threaded fastener with a polygonal periphery, having abutments extending outward from the junctions of the peripheral faces.

SUMMARY OF THE INVENTION Bolts and nuts have been subject to such intensive study and improvement for so long a time that we tend to presume that the remaining problems with them are inherent. This invention, however, has eliminated several of these without increasing the amount of metal required in the fastener. One of the most common types of threaded fastener has either a hexagonal or a square periphery for engagement with a wrench. In applying these fasteners where access is limited, some sort of special tool is often required to start the fastening, as it will not be supported by the wrench. It will fall through open-end or box wrenches, and will fall into or out of a socket wrench. This is prevented by the present invention through the provision of spurs extending out from the corners of the polygonal periphery. These spurs act as abutments limiting relative axial movement between the fastener and the wrench at that point. The bolt or nut can be placed in the wrench, which then becomes a placement tool, as well as a means of applying torque. Past developments have included a configuration in which a hex or square head was combined with a washer, but this arrangement tends to increase the amount of metal excessively. The vast numbers of these fasteners in general use brings the cost factor to a position of dominating importance. The spurs provided by this invention use a very small amount of metal, as they do not transmit bearing pressure. This feature makes it possible to form a nut incorporating the invention with the same amount of metal as a standard nut.

There are a number of auxiliary features of the spur configuration, one of these being the support of the wrench by the fastening in a position clear of a finished surface, so that rotating the wrench to tighten the fastening does not damage the surface. The spurs also make it easier to handle these fastenings when a mechanic is working with greasy machinery.

DETAILED DESCRIPTION The several features of the invention will be analyzed in detail through a discussion of the embodiments illustrated in the accompanying drawing. In the drawing:

FIG. 1 is a perspective view of a hex nut provided with the abutment spurs of the present invention.

FIG. 2 is a plan view of the nut shown in FIG. 1.

FIG. 3 is a section on the plane 33 of FIG. 2.

FIG. 4 is a perspective view showing a nut of the type shown in FIG. 1, supported in an open-end wrench.

FIG. 5 shows a bolt supported in an open-end wrench by spurs on the bolt head.

FIG. 6 shows a nut of a type shown in FIG. 1 engaged in a socket wrench.

FIG. 7 shows the manner in which spurs on the head ice of a self-tapping screw are used to support a wrench clear of a finished surface.

The nut shown in FIGS. 1 and 2 has six surfaces 10-15 forming a polygonal periphery for engagement with a wrench. The threaded interior 16 is coaxial with the hexagonal periphery, which is a standard configuration. At the junctions of each of the surfaces 10-15 (at the corners of the hexagonal configuration), a group of spurs 17-22 are arranged in coplanar relationship. These spurs are set back slightly from the bearing surface 23 to an axially intermediate position on the nut, leaving the major portion of the axial length of the surfaces 1015 unobstructed to receive the wrench. The axial length of these fastenings is usually determined by the length of threaded engagement required to transmit the stresses from the nut to the bolt, and not by the required length for receiving a wrench. The incorporation of the spurs therefore does not require an extra length to the nut.

In a preferred form of the invention, the spurs are formed by engaging a standard nut with a ring-shaped die from the direction of the bearing surface 23, the diameter of the die being slightly in access of the width of the nut across flats (which would be the distance between the surfaces 10 and 13). This distance is slightly less than the distance across corners of the nut, with the result that the width of the nut immediately under the spurs is slightly less than the distance across corners on the axially opposite side of the spurs. By forming the spurs in this manner, it will also be obvious that the bearing surface of the bolt, which is the effective bearing area of the surface 23, is not decreased. It is normally the practice to break the corners of a nut at both ends so that the corners of the nut do not dig into the surface against which the nut is being tightened. The distance between the points 24 and 25 will therefore represent essentially the same bearing surface as that of an unmodified conventional nut.

A nut modified as shown in FIGS. 1, 2, and 3 is easily held in an open-end wrench 26, as shown in FIG. 4. The nut 27 is supported by the spurs 28-31, and possibly additionally by the spur 32 (depending upon whether the nut is shoved as far as possible into the wrench). Held in this manner, the wrench becomes a tool with which it is very easy to install the nut on a downwardly-extending threaded projection where access may be quite limited. It is preferable to leave a small amount of the fiat on the sides of the nut after the formation of the spurs, so that there will be some small area for transmission of wrench torque with the nut inverted from the position shown in FIG. 4. It is only necessary to leave enough surface here for a slight amount of torque needed to start the nut, as the wrench can be disengaged laterally after starting so that the principal tightening torque can be applied to the axially opposite side of the nut. FIG. 5 shows the manner in which a bolt prepared with abutment spurs is supported in an open-end wrench for insertion from underneath. The head 33 of the bolt 34 is in essentially the same peripheral configuration as the nut shown in FIG. 1.

The nut 35 shown in FIG. 1 is handled in a socket wrench in a manner indicated in FIG. 6. The nut is supported in a position for upward installation 'by the engagement of all of its spurs against the end 36 of the socket 37. The socket is the essentially tubular member with its interior formed to engage hex at square fastening surfaces, and socket units of standard sizes are detachable from handle units 38. Were it not for the presence of the spurs on the nut 35, the nut would fall down into the tubular interior of the socket 37.

FIG. 7 illustrates the manner in which the presence of spurs on the head 39 of a self-tapping screw 40 are used to keep the box wrench 41 away from the finished surface 42 of a. machine housing being secured to an angular frame member 43. The surface 42 will commonly be painted, and the wrench 41 will often be replaced by an air-driven motorized socket Wrench. Without this invention or some more expensive arrangement, the wrench will slip axially down onto the surface 42, and mar it as the Wrench rotates. If access to the installation is limited, the screw 40 may be first placed in the box wrench in a manner similar to that shown in FIG. 5.

The particular embodiments of the present invention which have been illustrated and discussed herein are for illustrative purposes only and are not to be considered as a limitation upon the scope of the disclosed invention.

I claim:

1. In combination with a wrench, a fastening member having a polygonal peripheral surface coaxial with a threaded portion, said wrench having a fastener-embracing surface generally complementary to at least a portion of the polygonal peripheral surface of said fastening member, wherein the improvement comprises:

at least three equally spaced abutments extending outward exclusively from the junction of two of the faces forming said polygonal peripheral surface, said memher having a reduced circumscribed diameter extending axially from one end a distance limited to a minor portion of the length of said member, the diametral distance across the nut at one of said abut ments being greater than the distance between opposite portions of the embracing surface of said wrench, said projections constituting material deformed from the corners of the said fastening member.

References Cited EDWARD C. ALLEN, Primary Examiner US. Cl. X.R. 85-32 

